"This site is intended to provide a central database of guilds along with important information such as the server they are rolling on, their approximate member count, and their gameplay focus.
Currently you can browse guilds, browse servers, and submit guilds to the database (all guilds will be checked and approved by a moderator). "
http://www.gw2guilds.org/
Pretty cool if you ask me
Already 36 guilds registered. Its growing crazy fast.